The risk of Earth's species becoming extinct
will accelerate as global temperatures rise, new research
After reviewing more than one hundred scientific papers, the
study finds as many as 16% of plant and animal species on land and
in the oceans would be under threat with four degrees of
Climate change could even overtake habitat loss
and degradation as the main cause of extinctions, the lead author
tells Carbon Brief.
The rate at which plants and animals are
becoming extinct is now
a thousand times higher than before humans
inhabited the Earth.
Habitat loss is the principal cause of
extinctions, as forests are cleared and urban areas expand. But a
new study, published in
Science, suggests that climate change could
soon become a key threat to species around the world.
A warmer world could have many
different impacts on plants and animals, not
least by pushing temperatures beyond species' physical tolerance.
Shifting seasons can affect breeding patterns, and hot days may
mean animals have less energy to search for food.
Changes to rainfall patterns may affect
availability of water and freshwater habitats. These changes could
conspire to influence how much food a species can access, and what
predators and diseases it is exposed to.
The combination of habitat loss and climate
change is likely to intensify their individual impacts on different
species, Prof Joshua
Lawler, who wasn't involved in the study but who
is an author of the latest Intergovernmental Panel on Climate
report, tells Carbon Brief:
"[H]abitat loss and
fragmentation will make it harder for species to move to suitable
climates, and climate change will drive human migrations and shifts
in the distribution of cultivated lands which will, in turn, reduce
habitat for species."
In the new study, Prof
Mark Urban from the University of Connecticut
aggregates the results of 131 studies on extinction risk to give a
global picture of the risks posed by climate change.
current target for international climate
policy is to limit global temperature rise to 2C above
pre-industrial temperatures. Even with this level of warming, we
can expect to lose around 5% of species, the study
But as you can see in the graph below, the
predicted extinction percentage increases as global temperatures
rise beyond the 2C limit.
Predicted extinction rates from climate change
rise with global temperature. Blue bubbles show individual studies,
and their size shows how many species the study assessed. Source: